


Substitute

by Lauren (notalwaysweak)



Category: Discworld - Pratchett, Harry Potter - Rowling
Genre: Crossover, Gen
Language: English
Status: Completed
Published: 2006-04-29
Updated: 2006-04-28
Packaged: 2017-10-05 18:31:22
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 10
Words: 13,731
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/44762
Author URL: https://archiveofourown.org/users/notalwaysweak/pseuds/Lauren
Summary: <blockquote class="userstuff">
              <p>Discworld/Harry Potter crossover. L-space offers endless crossover possibilities. When Vimes, Carrot, Angua and Cheri enter the Harry Potter universe, chaos and Quidditch ensue. Discworld post-Night Watch; Harry Potter fifth year.</p>
            </blockquote>





	1. Prologue: Beating the Odds

**Author's Note:**

> Harry Potter characters belong to J.K. Rowling. Discworld characters belong to Terry Pratchett.

Carrot was trying very hard not to look down, and even harder not to open his eyes at all. The broom between his legs seemed far too flimsy to actually support him*, and though the rest of the team seemed perfectly all right with hurtling through the air at speeds faster than his snail's pace, he was going to stick to imitating a gastropod and hide in his shell, or rather his robes, which were almost too small (but showed off his physique perfectly, as Angua had noted before the game, almost making him late onto the field).

He cursed Fred Weasley. If Fred hadn't broken his godsdamned leg, Carrot wouldn't be here, and if Carrot weren't here he wouldn't be feeling like he was going to throw up. Or down, considering gravity.

Something whizzed past his ear. Carrot opened one eye and swung his Beater's club experimentally, and almost knocked Draco Malfoy unconscious.

'_Ironfoundersson_!' Hooch blew her whistle. 'No aggressive attacks on the Seeker!'

'Don't worry, Professor,' Malfoy said condescendingly. 'He couldn't hit me if he had both eyes open and was standing on the ground.' He grinned at Carrot, who gritted his teeth and hung onto the broom with one hand and the club with the other. Carrot knew that he could put Malfoy in the hospital wing for a week. He also knew that he wouldn't.

Fortunately, or possibly not, he didn't have to muse on the idea for long. One of the Bludgers flew towards him, he swung at it and missed (having his eyes open might have helped), and threw himself off balance.

As Carrot plummeted, he managed to think quite a lot. He wished he'd never gone anywhere near Unseen University, for one thing. He wished he'd never heard of L-space, either. He really wished he'd never agreed to help the Librarian look for that missing book in it. He also wished that the others hadn't come with him, because although he would probably survive the fall (or rather, the landing -- the fall was easy to survive), this was going to be very embarrassing.

Unconsciousness, when it came, was a blessing.

** [   
](substitute01.htm) **

* * *

*No, it's not a bad euphemism. It's not even a good euphemism.


	2. Chapter One: The Transition

'More crispy duckling!'

'The Bursar found it when he came to ask the Librarian for a book,' Ridcully said. 'The Librarian either can't or won't explain what it is. We thought you might be the best to come to.'

'Why?' Angua asked.

Ridcully shuffled his feet. 'You're the Watch,' he said. 'Don't you investigate strange things?'

Cheri peered dubiously past Ridcully at the... whatever-it-was, which Ridcully had prudently had cordoned off with a strong, invisible magical barrier, the only thing that would stop the wizards from going and poking... _it_ to see what it was, short of a sledgehammer to the cranium. 'Not quite this strange,' she said. 'Usually 'strange' means 'bleeding'. Or 'reluctant to talk', which is when Detritus steps in. Or _on_, depending on the level of reluctance.'

'We _could_ have a look, I suppose,' Angua said, stepping a little closer. 'I'm sure Commander Vimes would like to know that something odd's going on, even if we don't know exactly what it is.'

'I already sent Carrot to tell him,' Cheri said.

The two men in question entered the Library at that very moment.

'Alright, what's going on here?' Vimes asked.

'We don't know,' Cheri and Angua said in unison. 'We're hoping to find out,' Angua added. 'We just thought you should know. It looks important.'

Vimes squinted. 'It looks, Sergeant, like a swirly green hole in the middle of a bookshelf. It doesn't look important. It looks like a whirlpool in the Ankh, should the Ankh ever muster enough speed to have such a thing.'

'Well...' Cheri said, 'it does. But it's still a strange phenomenon.'

Vimes looked at Ridcully. 'You're wizards. You people write the book on weird things. We're surrounded by them. Why don't you know what this is?'

'That's exactly it,' said Ridcully, 'none of us have ever seen anything like this before.'

'Divide it by five,' said the Bursar.

'Just as you say, Bursar,' Ridcully said.

'Oook,' agreed the Librarian, who had come over to watch the others with interest.

'Shouldn't we at least try to do something about it, Commander?' Carrot asked.

Cheri edged closer to the... whatever. 'I think I can see something in it,' she said. 'Like there's a hole in the middle.'

'What can you see?' Vimes asked.

Cheri fished in her pocket and pulled out a magnifying glass. 'Ah,' she said. 'Just as I'd thought.'

'_What_?' Vimes had a baby son and a wife waiting for him at home, both of whom didn't take too kindly to him disappearing without warning, especially not during the first dinner they'd had together in the last week. 'Littlebottom, if you don't--'

'It's _books_,' Cheri said triumphantly. 'A shelf of books.'

'Brilliant,' Vimes said. 'So the hole in the shelf of books reveals, in fact, a shelf of books. Apart from the green glow, which could simply be a miscast spell, true?' -- this he addressed to Ridcully, who nodded -- 'this is a perfectly plausible happening in a library.'

Cheri leaned closer. 'They don't look like the rest of the books, though,' she said.

'Oook?'

'How so?'

'They're cleaner, for one thing.'

The Librarian sagged. His entire posture implied that he did his best, and that an orang-utan couldn't be expected to keep the place quite as spick and span as a human, even with the added duster in the form of his fur. Then he appeared to notice something, and drew himself upright again, which had the effect of making him look like an orange bagful of leaves suspended between two sticks.

'OOOK!'

'What's he pointing at?' Carrot stepped closer. 'There's a book missing.'

'Oook! Oook ik ook!'

'It might be in the hole,' Ridcully said, moving backwards and dragging the Bursar with him. 'Why don't you look?'

'Er, Carrot, it might not be a good idea for you to get that close,' Angua said.

If a list of Famous Last Words were to be compiled in Ankh-Morpork, those words would be on it, along with, 'What thieves' license?' and 'Vetinari? I always thought he was a bit... you know...'

In short, it wasn't a good idea. At all. Ridcully was right to have backed away, as the four Watchmen* vanished.

** [   
](substitute02.htm) **

* * *

*Or two Watchmen and two Watchwomen, or to be completely specific, one Watchman (dwarf by adoption), one Watchwoman (werewolf), one Watchwoman (dwarf), and one reluctant-Commander-of-the-City-Watch-who-was-meant-to-be-at-home-educating-his-son-in-the-ways-of-mushy-peas.


	3. Chapter Two: L-Space

It's difficult enough to study for exams at the best of times, especially when they're OWLs or your dimension's equivalent, and even if you are Hermione Granger, widely acknowledged as the most intelligent fifth-year at Hogwarts, despite mysteriously not being Sorted into Ravenclaw. So it doesn't help to be sitting in the library and suddenly have four people fall out of thin air beside you.

They didn't really fall out of thin air, Hermione decided a moment later. They'd fallen out of the bookshelf, but either way, she was on her feet with her wand aimed at them a second later.

'Who are you and why aren't you in uniform?' she demanded, mentally cursing her prefect's instincts even as she said it. It didn't matter, because she didn't get a response. The four people were too busy staring at each other to even notice her.

'Sergeant... weren't you older a minute ago?'

'I could ask the same of you...'

Hermione surveyed the four of them. All about her age, which was why she'd mistaken them for students, which they clearly weren't now she came to think about it, especially not the dwarf. All bearing identical expressions best described as 'huh?' -- and all wearing a strange uniform that, while neat (sort of) and shiny (especially in Carrot's case), was most definitely not Hogwarts standard.

'Who are you?' she tried again, keeping her wand up just in case. 'How did you get here?'

'Who are _you_?' Angua countered.

'I asked you first,' Hermione said.

'What's going on here?' an irate Madam Pince demanded. 'Miss Granger, I shouldn't have to tell you the rule about no raised voices in the... _who on Earth are you four_?'

'Earth?' four voices chorused.

Hermione gladly handed the reins of the situation over and fled, only to be collared a second later and marched up to Dumbledore's office.

* * *

'We have an extremely strange situation here,' Dumbledore said almost as soon as the six of them walked into his office.

'They just appeared in the library,' Madam Pince said, 'according to Miss Granger.'

'Out of nowhere,' Hermione said.

'_Really_ nowhere?' Dumbledore asked.

'No. More... out of a bookshelf,' Hermione said. 'But they weren't there before!'

'Indeed we weren't,' Vimes said. 'We were in the library of Unseen University.'

'And where might that be, young man?'

'I'll have you know I'm Commander of the City Watch, and...'

'And your armour is hanging off you,' Dumbledore said. 'Badly fitted. Which city?'

'Ankh-Morpork,' Angua said as Vimes rattled his breastplate and looked at the new gap between it and his chest. 'It's on the Discworld,' she added when Dumbledore merely looked gently puzzled. 'Surely you've heard of it?'

'I have heard of many places both far and near, young lady,' Dumbledore said, 'but never Ankh-Morpork.'

'What's he talking about?' asked Carrot, who couldn't whisper to save his life.

'I believe Madam Pince may have an answer for you.' Dumbledore gestured to the librarian. 'Go ahead, Irma.'

'The concept is simple enough, but I didn't think I'd see it employed by anyone so clearly not a librarian,' Madam Pince said. 'The theory goes that all libraries are connected in time and space by L-space.'* If her lips compressed into any thinner a line she wouldn't be able to speak. 'I shouldn't really discuss it.'

'This is an exceptional case, Irma,' Dumbledore said.

'You think they came from a different library?' Hermione asked.

'Precisely,' Madam Pince said.

'But we were different back there!' Cheri protested. 'Older, for one thing...'

'I believe that coming through L-space has altered time for you,' Dumbledore said. 'Your age has altered to be appropriate to the new place... to wit, you are now aged fifteen, just as Miss Granger is.'

'You can't be only fifteen, Cheri,' Vimes said, looking down at her. 'Not in dwarf years.' Cheri looked ready to axe someone who suggested such a thing.

'But how do we get back?' Angua asked sensibly. 'The hole closed behind us.'

'Oh dear,' Madam Pince said.

'"Oh dear"? I don't like the sound of that,' Vimes said. 'There had better be something better than "oh dear".'

'There will be,' Dumbledore said, 'and you can rest assured that I will do my best to find it. In the meantime, you should perhaps go with Miss Granger, who will find you beds and show you where dinner is served.'

'But we can't stay here!' Angua said. 'The city needs us!'

'The city will have to do without you for the time being,' Dumbledore said. 'You had best pose as students to avoid too many questions. It shouldn't be too difficult to do.'

'But I'm a _father_!' Vimes shouted. 'I have a son and a wife to look after!'

'Not here,' said Dumbledore. 'Here... you're a Gryffindor.'

[ **** ](substitute03.htm)

* * *

*Read _Guards! Guards!_ for more about this phenomenon, and also about Sybil Ramkin and dragons, which in my humble opinion is an excellent reason to read a book.


	4. Chapter Three: Sorting

Hermione, after some initial misgivings, had taken the foursome under her wing for the afternoon and spent it explaining the basics of Hogwarts.

'None of us are wizards,' Vimes had said.

Hermione raised an eyebrow. 'Well, I can't see how you would possibly get here if you weren't,' she had rebuffed him.

Then Carrot had spotted Nearly Headless Nick, and Hermione had worn a superior look for the rest of the day, because 'of _course_ Muggles can't see ghosts,' she explained. And had promptly spent ten minutes getting the concept of Muggles across to Carrot, who could be remarkably dense at times.

Vimes had spent much of the afternoon getting used to being quite a bit skinnier and wiry. Cheri had been counting her blessings that she wasn't any shorter. Whatever magic had brought them here had, thankfully, been logical enough not to regress her to the literal age of fifteen, which in dwarf terms would have made her barely out of kindergarten. Angua had tried very hard not to think about the approaching full moon. And Carrot... well...

The trouble was that Carrot had gone through puberty when he was still amongst the dwarfs. Being human meant that he'd gone through it a lot sooner than his dwarfish companions, however nature had managed to hold off for as long as possible. And now he was young again, and...

Suffice to say, he was keeping his legs crossed and his mouth shut.

* * *

A hush fell over the hall when Dumbledore rose to speak. Vimes, peeking around the curtain that separated them from the rest of Hogwarts, saw the rows and rows of earnest young faces looking up at the dais.

'Students, teachers... we have four new students joining us tonight.' Clearly he hadn't been any more able to explain their presence adequately than the foursome themselves. 'Professor McGonagall, if you would...?'

McGonagall, waiting with the four of them, ushered them out towards the waiting tables. The Sorting Hat was tucked under her arm, and she set a stool in front of the dais, then dropped the hat on it.

'What happens now?' Cheri muttered.

The hat opened its mouth (or that part of it which passed for a mouth) and sang:

'_Some might say that I'm old hat  
But I'm no crying shame  
For those who I Sort into their place  
May find fortune and fame._

_The knowledge was put into me  
To help you find your future  
Though I may look shabby  
As a guide you'll find none better._

_I know where to look inside your mind  
To find the place you will belong  
And I know how to Sort your abilities  
To make your powers strong._

_Hufflepuff's children are kind  
Ready to help their friends  
And if ever something might go wrong  
They're quick to make amends._

_Ravenclaw's people are wise  
Intelligence here is the key  
Their wit and wisdom makes them strong  
Theirs is a learning place to be._

_Slytherin's sort are a tricky kind  
Their powers those of cunning  
Rest assured, if you cross this type  
They will soon send you running._

_Gryffindor's type are mostly brave  
Courage and soul are just their style  
In Gryffindor you might just fit  
And thus go that extra mile._

_The Hogwarts' Houses each are fine  
And each have their own talents  
Each bring glory, pride and hope  
To each of their inhabitants._

_So when you put me on I'll tell you true  
Just where you ought to be  
And you will find that I'm always right  
Just try me out and see!_'*

'Oh,' said Cheri.

McGonagall consulted the piece of paper in her hand and called, 'Ironfoundersson, Carrot!'

There was a stir from the tables -- Carrot heard laughter from the table coloured in green and silver, which Hermione had told them was the Slytherin table. He picked the hat up, certain that it would speak again and tell everyone that this was a big mistake, that none of them were really wizards (or witches, he amended, looking at Angua and Cheri). He sat on the stool, which creaked.

Taking a deep breath, he put the hat on.

'Hello there,' said a small voice.

_Who are you?_ Carrot thought.

'I would have thought that was obvious.'

_Oh, the hat. Look, you know we're not really..._

'All I know is that you're not a Slytherin, m'laddo. Or a Ravenclaw, for that matter. You'd make a good Hufflepuff, you're honest and ready to work hard...'

Carrot looked out at the tables, spotting Hermione sitting at the table that bore a red and gold cloth. She was smiling at him.

'Gryffindor? Are you sure?'

_What are you trying to say?_

'I'm just trying to ascertain your reasons here,' the hat said, sighing. 'I suppose you're brave enough... yes, I think that'll do... GRYFFINDOR!' it shouted to the world at large.

There was the usual storm of clapping, although quite a few people were doing it with confused expressions. Carrot got up and put the hat back on the stool, and then walked to where Hermione, still clapping, had made room for him to sit.

'Welcome to Gryffindor,' she whispered, patting his hand.

Carrot was suddenly very, very grateful for the large quantity of tablecloth that had conveniently draped itself over his lap.

'Littlebottom, Cheri,' McGonagall called.

This time it took a raised hand from Dumbledore to stop the laughter from the Slytherins. Even some of the others were hard-pressed to keep from giggling. Cheri stalked over to the chair, idly swinging her axe; that seemed to stop the laughter more than anything else.

'Hello, Miss Littlebottom. Nice beard.'

_Just get on with it. And don't put me in Slytherin, because they'll have to change their colours to red and... more red._

'Fair enough. I know the place for you. RAVENCLAW!'

Though the four wanderers had discussed their possible placing extensively over the afternoon, they had never really considered the possibility that they would be split up. Cheri whitened, but then took the hat off and strode resolutely over to the table bearing the blue and bronze. People made space for her; one girl, with a large white bird on her shoulder, seemed particularly eager to welcome the newcomer.

'Vimes, Samuel.'

Vimes really didn't know what to expect when he put the hat on.

'Sam Vimes, eh? You know, that name almost sounds familiar...'

_How could it?_

'I don't know... anyway, we're not here to chit chat. You know, you almost remind me of Harry Potter. He had a lot of potential that could really be benefited by the strength of a house like Slytherin.'

_Not Slytherin!_ Vimes thought, completely unaware that five years earlier Harry Potter had thought the same thing. _Not Slytherin!_

'As you will, then... GRYFFINDOR!'

Vimes scooted off the stool -- he seemed to be all knees and elbows -- and dropped the hat back in its place before hurrying to sit with Carrot.

'Welcome to Gryffindor, sir,' Carrot said.

'You'd better not call me that here,' Vimes said.

'von Überwald, Delphine Angua!' McGonagall read.

'Just Angua,' Angua said.

'This is Harry Potter... Harry, Sam Vimes.' Carrot looked ill at ease with the familiar form of address. 'Ron Weasley... that's Neville Longbottom... Lavender Brown...' Lavender was already making eyes at Carrot, much to his embarrassment. 'Parvati Patil...'

_Typical Carrot_, Vimes thought. _He's known them five seconds and he already knows everyone._

'SLYTHERIN!' the hat shouted.

'What?' Carrot, Vimes and Cheri said in unison.

Angua stood up, taking the hat off and shaking her blonde hair free. She moved to the Slytherin table, disdaining the place Draco Malfoy had hurriedly made for her and sitting at the end of the long bench. She stared helplessly across the room at the other three, who could do nothing but stare back.

[ **** ](substitute04.htm)

* * *

*Originally written for _Harry Potter and the Dragon's Nest_, recycled here to save me from actually thinking.


	5. Chapter Four: Settling In

After eating their fill, the new students separated and went with their new housemates to their respective common rooms. Though the temptation was strong to attempt to stay together, they _were_ adults, capable of spending a few nights apart without hassles.

Except they weren't adults any more. Vimes followed Hermione and Carrot, feet taking note of the inconsistencies of the stone floors. They were children again here. Which was a bit of a setback, all things considered. Well. At least they weren't reliving their childhoods back on the Disc. He didn't think he could stand to go through all that mess again.

Hermione was chattering about the school, having apparently decided to pretend that they were just normal students. Vimes vaguely processed the information she was giving them and realised that whatever they'd stumbled into here, it was nothing like the brand of magic he was used to from Ankh-Morpork. First and foremost, the girls were treated equally to the boys, unlike Unseen University, whose alumni ranked 'girl' with other less savoury four-letter words, and blanched when it was mentioned. And then there was the fact that, while there were levels of magic being practised that easily equalled those back home, Hogwarts had never exploded.

He was disturbed from this train of thought when the staircase they were ascending began to swivel away from the corridor it joined with. Hermione let out a groan and jumped the gap, Carrot and Vimes following in rapid succession. Looking down, Vimes realised just how high they had climbed; the staircases criss-crossing the vast space below moved slowly, but he could see just how dangerous it would be for someone who wasn't paying attention.

They came at last to a portrait of a fat woman wearing pink, who could quite easily have been one of Sybil's ancestors. Accompanying her in the picture was a thin woman with a pointed face, who gasped and giggled when she saw Carrot.

_Typical_, thought Vimes. _Bloody typical_.

'Password?' the Fat Lady asked.

'Biting teapot,' Hermione said, shaking her head. 'These two are new students -- Carrot Ironfoundersson and Samuel Vimes.'

'Glad to know you,' said the Fat Lady, swinging forward to reveal a hole in the wall.

Hermione led them through the portrait hole into the Gryffindor common room (Carrot had to duck to avoid bashing his head on the stone lintel). The fire was keeping the room pleasantly warm and a few of the other Gryffindors were already there, toasting marshmallows and talking animatedly. The talking subsided when the trio entered, and Vimes inwardly sighed -- he knew when people were talking about him.

'Oh, hello,' said the boy who had been introduced to them at dinner as Ron Weasley. 'Welcome to Gryffindor.'

'Delighted,' Vimes said. Carrot cast a sideways look at him, evidently trying to decide whether he was being serious or not. Vimes kept his face carefully blank as he crossed the room to where two wooden boxes sat on one of the larger tables. He had spotted his name on one of them, and attempted to look as if he knew what to expect when he opened it.

Someone had obviously gone to a bit of trouble to make it look like they belonged. The box contained an armload of black material, which when he shook it out turned out to be black robes like the other students wore.

_Wait. _Other_ students? You're not one of them, Vimes, you're a father and a husband and a Watchman, not some kid with a wand and a pointy hat._

There was a shirt and a pair of trousers underneath the robes. Underwear. Socks. A pointy hat, which Vimes immediately resolved never to wear. He was aware of Carrot standing beside him, digging into his own heap of new things.

A pile of books had a note taped to the top:

> _Samuel Vimes:_
> 
> _We have put you and the others with the fifth-years, but since you have no prior magical knowledge we may have to put you with the first-years instead if your talents do not prove to be strong enough. You have been provided with everything you will need for the time being. The Headmaster is doing his best to remedy the situation._
> 
> _Professor M. McGonagall_

The thought that Professor McGonagall had packed this for him only made Vimes twitch when he remembered the underwear.

Underneath the books was a box. A long, thin box. Vimes lifted it out and untied the ribbon around it. _Ollivanders_, the lid proclaimed. He lifted the lid off and blinked at what was inside.

'Is that rosewood?' Hermione asked, standing next to him. 'What's the core?'

'Dragon heartstring,' Vimes said automatically, then blinked again. However, Hermione seemed to accept this as a normal answer, no matter where it had leapt from. There was a piece of paper in the box, and when Vimes read it, he realised he was right. Rosewood and dragon heartstring, seven and a half inches. Made by Ollivanders for the discerning wizard, which he most definitely wasn't.

_How did I know that?_

'What's yours?' Hermione was asking Carrot.

'Oak and unicorn hair.' Carrot held it up uncertainly, then remembered they were supposed to know what they were doing and flourished it instead.

'Oh dear,' Hermione said a minute later when the smoke had died away. 'Perhaps you'd better go to the infirmary.' She patted Carrot on the arm. He blushed, as far as Vimes could tell through the soot. 'I'll take you.'

Well. At any rate, this was going to be more interesting than trying to persuade Detritus to load the Piecemaker with only one handful of arrows at a time, or reprimanding Nobby for pinching the tea money, or changing baby Sam's nappy.

That last thought brought a tear to his eye, but Vimes wiped it away quickly, and set about learning how to be fifteen all over again.

* * *

The Ravenclaw common room was almost as full as its Gryffindor equivalent, but instead of merry voices and the crackle of the fire, the only sounds were the occasional turning of a page and the various students breathing. Even the fire had been muted to prevent distraction.

Cheri was bored already.

It looked like she was going to keep her alchemical skills somewhat in practice, because they had Potions class and no matter what Kyla (the girl she had met after the Sorting) said, Cheri reckoned she could deal with any tetchy teacher who tried to correct her.

Kyla was currently over in her own corner, feeding Tindysquawk, the big white bird that had been sitting on her shoulder at dinner. He was a bird she had brought over from Australia and seemed more interested in trying to nip her nose than in the pieces of fruit she was offering him.

Like the two 'Gryffindor boys', Cheri had also received a boxful of important items on her arrival at the Ravenclaw rooms. Her wand had been only five inches long. Whether this was normal or someone's idea of a joke, she wasn't sure, but she'd already managed to shoot sparks from it into the fire, making it crackle and pop and getting the attention of most of the students surrounding her. If she was going to be stuck here, then she was damn well going to do it right and learn some magic.

Her robes had trailed two feet behind her when she first tried them on. Kyla had shortened them with a charm and Cheri had memorised the words that she had used. If anyone made fun of her height, she was going to use it on them, and bugger the consequences.

Kyla finished feeding the sulphur-crested cockatoo and let him fly out of the window, which was high up in the wall. They had gone downstairs after dinner, and Cheri's dwarf senses told her that this room was underground, at least partly. It made her feel comfortable, especially when Kyla led her down a second flight of stairs to the girls' dormitories.

A bed had been made up for Cheri in a corner, and when she finally managed to get in it (after almost an hour of rigorous questioning from Kyla, who wanted to know where she'd come from, a question Cheri had difficulty answering, given the truth) she could feel the earth on the other side of the solid grey stones.

In that way at least, it was almost like home.

* * *

Angua, in the Slytherin girls' dormitory, was feeling far less happy about her surroundings. Pansy Parkinson was ostensibly reading, sprawled on her own bed, but Angua could feel the girl's eyes on her. Still, it was better than what she'd been enduring in the common room -- at least she could be fairly sure that Pansy wasn't trying to undress her with her eyes, like Draco Malfoy had been.

She wished she could get out and see Carrot at least. He had looked shocked when the Sorting Hat had announced its decision... she could still hear its voice, like it was pronouncing a sentence rather than just allocating her a place to sleep and study.

'Delphine Angua von erwald, eh?'

_What about it?_

'Hmmm. Definitely not Hufflepuff material. There's something else there, though...'

_If you can see what I am, don't beat around the bush._

'I can see what you are. And that's why I'm going to put you in... SLYTHERIN!'

The only ones who'd been at all pleased about this result were a few of the Slytherin students. Like Malfoy, who for some reason smelled the way she remembered ferrets smelling, small and fierce. Pansy, on the other hand, just smelled angry. The anger had grown stronger when Malfoy had made room for Angua at the table, although it had faded a little when Angua had declined the space.

The last thing she wanted was _that_ sort of problem on her hands. Or paws. In fact, paws were going to be a bigger problem. She hadn't told Dumbledore that she was a werewolf, or anyone else for that matter, but that hat was probably going to spill the beans. And judging by the enchanted ceiling in the room where they'd eaten, the full moon was only a few days from spilling the beans for her anyway.

She wondered where she'd go. The chances were good that there was no way she was going to be able to sneak out without Pansy noticing, since Pansy's bed was between Angua's and the door. They were too deep underground for windows -- the whole place smelled dank and damp because of it -- so she couldn't do a runner that way.

Well. It was her problem; she'd find a solution. She always had.

Curling up to go to sleep a few minutes later, she reached out instinctively for Carrot and almost burst into tears when she remembered that he wasn't there.


	6. Chapter Five: Making Magic

They didn't even have a grace period to get used to the place before they were plunged headfirst into classes.

The Gryffindors began the morning with Charms. Professor Flitwick was the only person they'd seen so far who was anything like as short as Cheri, and Vimes wondered if this place didn't have dwarfs at all... or maybe they were just discriminating.

He'd seen some small children who had had to be first-years, clowning around at breakfast: they had more talent than Carrot, who was trying to figure out which end of his wand was which. Fifth-years? Hah. Hah, hah, and was that the Professor trying to get his attention? It was. Vimes sat up straight, trying to look like an attentive student, then remembered he'd never been one before and it was going to be difficult to start now. Beside him, Carrot was painfully straight-backed, looking directly at Flitwick, and only someone who knew him as well as Vimes did would be able to recognise the tension underlying the apparent readiness to learn.

'Today,' Flitwick said, 'we will begin the first basic charms for Apparating objects.'

A murmur of excitement rippled through the class. Obviously Apparating was something special. Vimes looked around. Harry was slouched in his chair, but looked attentive, whereas Ron was just slouching. Hermione sat bolt upright, quill clutched tightly in her hand, book open in front of her.

'To correctly Apparate or Disapparate an object takes a good deal of concentration. You all know, of course, that a person cannot Apparate or Disapparate within the castle or its grounds. This is for the safety of Hogwarts, to protect you all. However, the minor charms of this type can be used.' Flitwick pointed his wand at the topmost of the books teetering precariously on his desk. '_Libro evanesco_.' The book disappeared. 'This initial charm merely makes a book vanish. The counter-charm is _Libro appareo_. Do not attempt to use this charm on anything bigger than a book... fellow students are _right_ out.' There was a dutiful giggle. 'Split into pairs and try it.'

Vimes turned to Carrot, already prepared to make a scathing remark about how this really, really wasn't going to work, and saw Carrot's face, scrunched up in concentration. Carrot lifted his wand and pointed it at the book.

'_Libro evanesco_.'

The book vanished.

* * *

Underground they might be, but the dungeons smelt nothing like home. Cheri didn't have Angua's nose when it came to such things, but she could smell the difference between a cosy underground home and Snape's laboratory, which smelt of rancid grease (probably his hair) and long-dead _things_. She shuddered as she sat at one of the long benches. The high stools that were too tall for most of the humans to manage were the right height for her to sit comfortably, but that was the only good thing about this dank room so far.

Kyla patted her on the shoulder. 'You get used to it,' she whispered in an undertone not intended to carry to the front of the classroom.

'Miss Anderson.' Snape's voice was cold. 'When you have finished your conversation with Miss Littlebottom, perhaps you would be so kind as to allow _me_ to get on with teaching you something?'

That day's potion was a noxious brew that, Kyla explained, they'd begun the previous week. It glopped in the cauldron and reeked hideously of herbs Cheri was sure she wouldn't even be able to begin to hazard a guess at naming.

'Tarragon,' Kyla said when she asked, 'and angelica. And mint. Although,' she added, 'I think the mint's just for flavouring.'

Cheri poked a cautious finger into the mixture and licked a drop. It didn't taste too bad, actually. Sort of like... mint. She didn't want to think too much about the other taste that the mint masked.

'So what's it do?'

'You just _tasted_ it,' Kyla said. 'Have you got a death wish, or something?'

Cheri paled. 'No. Why? Is it poison?'

'Worse,' Kyla said. 'It's a truth serum. Although I shouldn't think that little lick will do you much damage. Word of advice: don't taste _anything_ in here if you don't know what it is.' Snape swept by them, dark and foreboding. 'Mind you,' Kyla went on, 'swallowing poison'd be preferable to failing, really.'

'I don't want to think about it,' Cheri said firmly, taking the ladle from Kyla and stirring the cauldron vigorously. 'I'm not going to be here long enough to fail.' Another dollop of the mixture splashed out onto her fingers and, without thinking, she licked it off.

'Why? Where did you come from?'

'Ankh-Morpork,' Cheri said before clapping her hand over her mouth.

'You _what_?' Kyla looked at the residue of potion on Cheri's fingers. 'Oh, _shit_. Sorry, Cheri, I didn't realise you still had the potion in your system. I won't tell anyone. _Ankh-Morpork_!'

'You know where it is, don't you?' Cheri asked. 'You know the name!'

Kyla nodded. 'Yeah. It's a place in a series of books I read. I thought your name was familiar. How the hell did you get here?'

_Has the potion worn off?_ Cheri wondered, before realising the answer was the same either way. 'I don't really know.'

'Ye gods and little fishes. Interesting. Interesting, interesting. Coming here from Australia is one thing. Coming here from another dimension entirely...'

'I'm not really supposed to talk about it,' Cheri said, not wanting to yell at this friendly girl.

'Mmmm, sorry. We'll talk in private.' Kyla glanced around. 'I think this potion is about ready.' She scooped up a ladleful and poured it into a vial without spilling a drop, corking the vial and sticking a label with her name on it on the side. 'You can start making potions yourself next class.' She carried the vial to the front and placed it in a rack on Snape's desk. As soon as Kyla had her back turned, Cheri scribbled in her notebook, attempting to copy the potion ingredients from the blackboard. A truth serum, if it worked as well back home as it did here, would be _invaluable_ to the Watch! Forget using entrapment on Done It Duncan to see if he'd inadvertently give up a name. With this, there'd be no doubt about guilt! Provided, of course, that they could catch the culprit. Provided, of course, that she ever got home at all...

* * *

With the classes ranging all over the castle, it wasn't until after the Gryffindors' second class of the day -- Care of Magical Creatures, a session consisting entirely of feeding insects to Jobberknolls -- that Vimes and Carrot could meet up with Cheri and Angua at lunchtime. Selecting a plateful of sandwiches each, they disdained the house tables and went outside to eat.

Angua was sullenly quiet. Carrot attempted to put an arm around her, but she was so tensely stiff that he gave up and settled for patting her hand.

'How did you go?' Vimes asked Cheri.

'I had Potions, then Divination.'

'Did you... get anywhere with them?'

'In a manner of speaking,' said Cheri, thinking of the Potions notes she had written down. Surely all the ingredients would be available back home? 'D'you know what a Jobberknoll is?'

'We just spent an hour feeding them bees,' Carrot said. 'Why?'

'What are they and can we get some of their feathers?' Cheri explained about the truth serum, watching Vimes's face light up. 'I think it would be really useful back home.'

'Sounds like it. Listen, did you really try any other kind of magic? Carrot did, and then I did, and it actually _worked_,' Vimes said.

Angua let out a sort of choked giggle.

'Angua? What's wrong?' Carrot asked.

'The magic works. We can make it work. Why? Why does it work for us? We're not wizards, none of us are, we're just... _Muggles_, really, aren't we?'

'What happened, sergeant?' Vimes asked.

Angua started giggling again. 'I'm not a sergeant any more, sir... Sam. I'm Miss von erwald to the teachers... especially the Headmaster.'

'Why did you have to go and see the Headmaster?' Vimes asked suspiciously.

'I... I had Transfigurations for my first class. And we were talking about how in Transfiguration you look for similar properties between what you have and what you want -- I think that was for my benefit, everyone else seemed to know it already. And Malfoy smells like a ferret...' Angua lost control of her voice and just laughed.

'You turned him into a ferret, didn't you?' Vimes asked.

Angua nodded, tears of laughter running down her cheeks. Cheri snorted. Carrot was valiantly trying not to laugh, but started giggling anyway. Vimes gave in, his stern face crumbling into chuckles.

They were all still laughing when Malfoy walked past, his face deliberately turned away from them. They still saw the long white whiskers, though... and the bushy white tail poking through a slit in the back of his robes.


	7. Chapter Six: Full Moon

Three days after the ferret incident, Hermione came bursting into the Gryffindor common room, where Harry and Ron were explaining Quidditch to Carrot and Vimes.

'Madam Pince thinks she's worked it out!'

'Worked what out, Hermione?' Harry asked, catching the miniature demonstration Snitch between his fingers and tucking it back into its box.

'How to get Sam and Carrot back to where they belong, of course.'

After Cheri's accidental revelation of their origins in class, which had been overheard by a number of the other Ravenclaws, rumours had spread, as rumours are wont to do in such situations. Cheri had thought about Kyla's statement that Ankh-Morpork was a place in a book and then reported it to the others, and Hermione had overhead the word 'book' and pricked her ears up instantly, and things had snowballed in every direction from there, most particularly towards the library and a certain gap upon a certain shelf. The Hogwarts library stocked a small section of fiction books for those students who preferred to spend their limited leisure time reading something other than thick tomes on Transfigurations and the like, and it was through this section of shelves that the Discworldeans had first entered Hogwarts.

'Let's hear it then,' Ron said.

'She thinks that they got here through L-space. Apparently all libraries are connected by it. One of the books is missing from the shelf.' She looked at Carrot and Vimes, who were hanging on her every word. 'If you can find that book and replace it in the gap, you'll be transported back through L-space, back to where you come from.'

'How does it work?' Vimes asked.

'Well, Madam Pince wasn't entirely sure about that, but you have magic in your world and we have magic in ours, so she thinks it might be the mundane books in the magical libraries absorbing magic that they're not supposed to hold, and releasing it as some kind of portal.'

'Are you trying to say that in _their_ world, there's a book about us?' Harry asked. 'That's... it's...'

'_Wicked_!' Ron said. 'I bet I'm the star. Poor downtrodden boy from huge family becomes Quidditch hero and...'

'...Bighead Boy,' Harry finished.

'It could be me,' Hermione said. 'I never knew anything about magic until I got my Hogwarts letter. Muggle-born girl becomes greatest witch of all time.'

'I didn't know anything about magic either,' Harry said, determined not to be outdone. '_And_ I was more downtrodden than you, Ron. I could be the star.'

Carrot and Vimes exchanged a glance, suddenly feeling much older than their current physical appearances suggested. 'Where's Angua?' Vimes asked, in an attempt to change the subject.

Carrot shook his head. 'I haven't seen her all day. It's...' He glanced at the other three Gryffindors, who were energetically bickering about which Muggle movies stars would play them in the movie version of their lives, and drew Vimes a few steps further away. 'It's her time of the month.'

'_Oh_,' Vimes said. Not for the first time, he wished Sybil were with them. Even as a fifteen-year-old she would undoubtedly be Sensible; she would Sort Things Out and Make It All Better. And she'd probably excel at Care of Magical Creatures. Hells, _she'd_ teach things to _Hagrid_. At the very least she'd be able to think of a way to explain to Professor Snape that one of his students was mere hours away from becoming a wolf. 'Do they even _have_ \- her kind - here?'

'Page forty-one of _Fantastic Beasts and Where to Find Them_,' Carrot said. 'But sir-'

'Sam,' Vimes corrected him.

'Sam, it says that they're murderous beasts here! Angua wouldn't kill humans for fun! She only kills chickens, and even then she's always upset!' Carrot's voice had risen during his little speech, and Vimes realised that Hermione, Harry and Ron were staring at them. He tried to silence Carrot, but it was too late.

'What're you two talking about?' Ron asked.

'It's Angua,' Carrot said. 'She - she's a-'

'Werewolf,' Hermione said, her tone businesslike. 'I've read _Fantastic Beasts and Where to Find Them_ too, you know.'

'But she's not _like_ that,' Vimes said. 'She doesn't kill humans. Not the way the book says werewolves do.' He swallowed. Asking a bunch of kids for help - it wasn't beneath him, but it _was_ embarrassing, even if he was one of them, if only temporarily. 'What should we do?'

The Gryffindor trio exchanged a glance, and Vimes felt for a moment almost as if they were somehow communicating mind-to-mind. When all three of them said, 'The Shrieking Shack,' at the same moment, he was sure of it.

'The _what_?' Carrot asked.

'It's a house in Hogsmeade,' Hermione explained. 'There's a secret passage to it. We can take Angua there this evening.'

'Not all of us,' Harry said, 'we won't fit under the Cloak.'

'How do we get her out of the Slytherin rooms without anyone noticing?' was Ron's question.

Hermione flicked her hair out of her eyes. 'We don't,' she said. 'We'll take her just after we eat tonight. But we'll have to tell Dumbledore.'

'Why?' Carrot asked. Vimes wasn't sure why Carrot sounded so defensive until he thought about it and realised that perhaps the stigma of being a werewolf was stronger here than at home. If he were Carrot, he wouldn't want his girlfriend branded with that particular sort of infamy either. 'Can't we just take her out to this place tonight and then bring her back tomorrow morning?'

'We need to at least tell Dumbledore and Madam Pomfrey so that we can pretend that she's in the hospital wing, or Pansy Parkinson and the rest of her snotty crew will cause trouble,' Hermione said. 'I'm sorry, Carrot, but Dumbledore won't tell anyone else.'

'How do you know?' Carrot asked.

Vimes listened with half an ear as the trio began to explain, something about a man named Lupin (Vimes hoped it wasn't his first name), but he was distracted somewhat by Neville coming in through the portrait hole. No... it wasn't Neville's entrance that had caught his attention, but a noise outside. It was a distant noise, but it roused all his senses, until he could put a name to it.

'Sir?' Carrot was _never_ going to remember not to call him that. 'What's the matter?'

'Someone's screaming,' Vimes said flatly. And then he was off and running, the other four hot on his heels.

* * *

They found Pansy Parkinson with her back pressed against the wall near the hallway leading down to the Slytherin dungeons, Angua standing with her head lowered and hands raised in front of her, Draco Malfoy a few paces away. The three of them were frozen in place, though Angua was making a low growling sound in the back of her throat.

'_Angua_!' Carrot's shocked voice cut through whatever primal urges had wrapped Angua's brain, and she turned to him, the angry expression on her face fading to be replaced by a look of confusion. She stepped away from Pansy and Carrot gathered her into his arms, holding her close.

'What's going on here?' Vimes asked, only just remembering not to shout; he was a student here, not a copper.

Pansy mumbled something incomprehensible. Malfoy moved to her and put a hand on her arm, but she slapped it away and then turned and fled. Malfoy cast one glare at Angua's back and followed Pansy.

'Must be something serious, he didn't stop to have a go at you, Harry,' Ron said.

Angua lifted her head from Carrot's chest and looked around at them. 'Please,' she said, and her voice held a note of fear, something Vimes didn't think he'd ever heard from her before. 'I need somewhere safe.'

'I'll find Crookshanks and we'll go to the Shrieking Shack. Harry, go and explain to Dumbledore and Madam Pomfrey where we've gone and why and then come and meet us. We need to move fast.' Hermione sounded bossy, but Vimes had to admit that she was well-organised.

* * *

The Shrieking Shack smelt of dust and every surface seemed to be covered in cobwebs. They settled into a disused living room; Hermione delegated Ron to fetch extra chairs from one of the other rooms and started blasting the grime away with twitches of her wand.

They were safe from anyone listening in on them here, and it gave Angua a chance to explain what had happened.

'That _ferret_ tried to kiss me,' she growled, her fingernails digging into the faded upholstery of the chair she was sitting in. 'Pansy thought I started it, and threatened me with her wand. I think - I might have started Changing.'

Vimes groaned. Judging by _Fantastic Beasts and Where to Find Them_, werewolves were not nearly as socially acceptable here as back home, and Hermione confirmed this by telling them the story of Professor Lupin, a werewolf who'd been barred from teaching at Hogwarts. It was a pity, because at least a werewolf on staff would've known how to handle things.

'But _we_ know how to handle this,' Hermione said. 'We've done it before. Right, Ron?' Ron, probably thinking about just what had happened last time they had had to deal with a werewolf, declined to say anything. 'And it's only for a few days a month.'

Angua looked very vulnerable as she sat in her chair, knees drawn up to her chest, her arms wrapped around them as if letting go would let the wolf explode from her. It occurred to Vimes that she probably hadn't lost all that many years as they aged backwards to fifteen. It also occurred to him that while Angua-at-home was a grown woman, able to keep the wolf under control, he had no idea whether Angua-at-Hogwarts, a teenager in an unfamiliar place, would be able to maintain the same control.

None of them said much after that for a long while. Angua visibly stiffened when the sound of footsteps echoed through the house. Carrot put a hand over hers, trying to soothe her, but she didn't relax until Harry, followed by Dumbledore, came into the living room.

'Miss von erwald,' Dumbledore said. 'I was expecting this.'

'You _were_?' Angua's voice was the loudest, but she wasn't the only one to ask. Hermione looked amazed, for one. 'How did you know?'

Dumbledore sat on the edge of one of the dining-room chairs that Ron had brought in, sending up a cloud of dust as he did so. 'I would be a very poor Headmaster if I had no idea what was going on in my own school,' he said mildly. 'But more importantly, I have known and worked with werewolves in the past, and I know what signs to look for.'

Angua, her ash-blonde hair half-shielding her face, her teenaged body awkward, folded up in the chair, didn't look at all like someone prone to howling at the full moon, but Vimes had the feeling that if Dumbledore said he could sense such things, then he could. After all, Hermione had mentioned something about one of their past professors being a werewolf. And even back home there were ways of telling who was a werewolf and who was a vampire, who were zombies or ghosts, who was the guilty party in a line-up, who was a Watchman in plainclothes and which person in a room had the highest social status. When you lived in a society with those sort of people long enough, you learned to recognise them no matter what they were wearing, no matter where they were or what they were doing.

Angua lifted her head. Her eyes were red.

'I think you'd better leave,' she said in a thick voice that sounded as if her throat wasn't quite hers. Carrot tried to hold onto her hand, but she pushed him away. Avoiding the hurt look on Carrot's face, Vimes looked towards the window and saw the moon, a just-rising sliver on the horizon.

'Come on then. Cheri will be going mad. We left without telling her,' he said, gently pulling Carrot away from Angua.

'Back to the castle, all of you,' Dumbledore said. 'I will join you shortly.'

'But-' Carrot started.

'Off you go.'

Vimes led Carrot out of the room. Ron, Hermione and Harry followed them, Hermione looking back over her shoulder.

'It's not _fair_,' Carrot said.

'At least she's got somewhere to Change,' Harry said comfortingly. 'Dumbledore will look after her, you'll see. Everything will be all right.'

Judging by the look on Carrot's face, it wasn't clear whether Carrot _did_ think everything would be all right.


	8. Chapter Seven: Quidditch Season

_ _

There was nothing quite like Quidditch back home in Ankh-Morpork, Vimes thought, sitting in the Gryffindor stands and watching the tryouts for new Keeper. There was Carrot's football, but it hadn't quite caught on yet. There was that game that certain people played that used wooden sticks, but that was known as 'mugging' rather than 'Beating', although he could see the potential for the same sort of outcome - those Bludgers looked extremely solid. If Detritus were here he'd make a good Beater, although Vimes didn't think there was a broom made that would hold the troll.

Angua came up the steps to sit down beside him, even though some of the other Gryffindors gave her funny looks.

'Feeling better?' Vimes asked.

She gave him an annoyed look. 'You've asked me that five times today, you know. It's been _days_ since the full moon.' She had come back from the Shrieking Shack looking pale and exhausted, but unharmed. There had been a couple of chicken feathers stuck to her robes.

Vimes nodded. 'Four of them. I'm just being careful.' He nodded at the Slytherin stands, where, although this was a Gryffindor tryout, three or four students were huddled, whispering. 'Pansy Parkinson's got it in for you.'

Angua rolled her eyes. 'Tell me something I didn't know.'

'Carrot's trying out for Keeper?' Vimes tried.

Angua's eyes widened. 'He is? He didn't tell me!'

'He didn't think he was going to do very well.' Vimes looked down at the Quidditch pitch. 'If he could get on the broom it would be a good start.'

Down on the grass, Carrot had persuaded his broom to hover, but every time he tried to swing a leg over it, it darted away and he almost fell over. Ever patient, he would catch it and start all over again, to the accompaniment of giggles from the Slytherin stand.

'I don't believe it!' Angua said suddenly. 'They're casting a spell on the broom!' She scrambled down the stand and marched straight across the Quidditch pitch. Vimes leapt to his feet and chased her, but Angua was angry, and when Angua was angry, she tended to get her own way. He could hear her yelling even before he stepped onto the Slytherin stand. Hells, they could probably hear her up at the castle. All action had stopped on the pitch, as Angua railed at the quartet of Slytherins (Pansy, of course; Malfoy; Malfoy's two goons) about safety and respect and exactly what she planned to do to them if she ever caught them doing anything of the sort again. They withstood about half a minute before slinking away.

After all that, Carrot seemed to be put off his game. Though he could finally mount the broomstick and fly a few practice circles close to the ground, flying up to the goal hoops was evidently beyond him.

'Never mind, Carrot,' Fred Weasley said, clapping him on the back (once he was safely landed, of course; the Gryffindors weren't in the habit of endangering their own fliers). 'Keep practicing - we can see you've got talent in there somewhere.

'Possibly buried quite deeply,' George Weasley put in.

'Still, it won't hurt to learn to fly,' Carrot said to Vimes as they, and Angua, wandered back towards the castle. 'It's quite exhilarating, really, being up in the air.'

'I'll stick to the ground, thank you,' Vimes said firmly. 'Running across rooftops back home is enough excitement for me.'

There was a rustling in the bushes, and Pansy and Malfoy stepped out onto the path in front of them; looking over his shoulder, Vimes realised that Crabbe and Goyle were behind them.

'Hello, children,' Pansy said.

'What do you want, Parkinson?' Angua snapped. 'I thought I made it perfectly clear that you were unwelcome.'

Pansy grinned. Vimes had seen his share of unattractive people in his time, but Pansy Parkinson smiling was a sight to behold. The effect could, perhaps, be best described as that of a pug dog with far too many teeth and garish red lipstick, crowned with too-shiny black hair that hung around her excessively pierced ears. 'We left the field,' she said. 'The path to the school's not the same thing.'

Angua made to push past her, but Malfoy grabbed her arm and sort of swung her backwards, so that she stumbled into Carrot. 'We think you need a lesson on what it means to be a Slytherin,' he said. It would probably have been more menacing if his voice hadn't cracked mid-sentence. 'For a start, we don't like Gryffindors, do we, Crabbe, Goyle?'

'Nuh,' Crabbe said.

'Gryffin_dorks_,' Goyle said. 'Hur hur hur.'

Vimes rolled his eyes. Those two were thicker than Detritus, and that was saying something. 'How did you teach them to talk, Malfoy? Freeze their brains?'

'What?' Malfoy clearly didn't get it. Vimes itched to lock him in a room with Detritus and the Piecemaker for a few minutes. _Then_ he'd understand.

Something else rustled in the bushes behind Malfoy.

''scuse me,' said Cheri. 'No, down here. Down... that's it,' she added, waving at Vimes, Angua and Carrot with one hand and splashing something into Malfoy's face with the other. 'Thank you. Much obliged.'

Malfoy didn't hear her gratitude. Malfoy was too busy screaming.

'What did you do to him?' Pansy yelled.

'Just a spot of potion,' Cheri said. 'It'll wash off. Although he might stay that colour for a while.'

Taking advantage of the distraction, Vimes pushed past Pansy. Malfoy had dropped to his knees and was rubbing at his eyes with both hands, howling, but if they didn't move quickly he'd probably recover - Vimes didn't know what the potion was, but Malfoy's face was now splotched an unattractive green, and a scatter of yellow pustules had burst out across his forehead and cheeks.

'Cheri, you got here just in time.' Vimes grinned down at her.

Cheri calmly tucked the now-empty potion vial into a pocket and grinned back. 'Well, I couldn't abandon my fellow Watchmen to the Slytherins, could I?'

Carrot and Angua joined them, and the foursome started back along the path.

'But how did you know we were in trouble?' Vimes asked.

'I didn't really, I was just coming down to see if I could find you. It's almost time to eat, and I was wondering if either you or Carrot were going to be on the Quidditch team.'

'Carrot tried out, but he needs more practice.'

'Oh, good.' Cheri looked visibly relieved. 'You see, Cho Chang was talking to me and got me on a broom this morning when we had some spare time, and I'm one of Ravenclaw's Beaters.'

Vimes choked. 'You _what_?'

'She said that as long as I could keep my balance I had the right body build to really swing the club, and a Beater needs to put a lot of force behind a hit, because Bludgers are hard to deter from their chosen path.' Cheri looked smug.

'Ri-ight.' Angua didn't sound like she thought it was a good idea. 'Cheri, are you sure you want to be anywhere near those things?'

'It'll get me into the fresh air,' Cheri said. 'The Ravenclaw rooms are underground too, you know.'

'What was that potion you threw on Malfoy?' Vimes asked, keen to head any potential arguing off at the pass.

'Oh, a bit of this, a bit of that,' Cheri said. 'Bit of Bubotuber pus, bit of permanent green fabric dye, bit of wishful thinking, really.' When she was at home and made a new alchemical discovery that would push her forensic work forward by several stages, she spoke in the same casual tone, but Vimes had learned to recognise it as a sign that she was actually quite pleased with herself.

'Good for you. He needed it,' Angua said. 'And hopefully it'll stop him thinking he's the most beautiful man in the world.' She turned to whisper something in Carrot's ear that made him blush a shade of red Vimes had previously seen only on beetroot.

Cheri snorted. 'Well, that's Slytherins for you. Always thinking they're better than anyone else.'

'_What_ did you say?' Angua growled.

'Calm down, Angua! You're not a Slytherin. You're a Watchwoman, and you'd better remember it,' Vimes said.

Angua sighed. 'You're right. Sorry, Cheri. I mean, this _is_ only temporary.'

* * *

But as the days wore on, and Christmas drew nearer, their situation seemed to be anything but temporary. Madam Pince was working every spare minute to try and determine which book was missing from the library shelf, but even when, in late November, she told them it was a book called _Night Watch_, it didn't mean much to the Ankh-Morporkians. Although they now knew the title, even Madam Pince's renowned library search spells failed to turn up the missing volume.

'It might have been sucked into our world,' Angua said glumly about a week before Christmas. 'If we got pulled through to this world, there's no reason for it not to have been pulled through to ours.' She made a snowball and tossed it in the general direction of the Quidditch pitch, where Carrot, Harry, Ron, Cheri and a handful of other Gryffindors and Ravenclaws were playing a pick-up game of Quidditch.

'You can't think like that,' Hermione said. 'Letting yourself get depressed won't help at all.'

'I suppose not.' Angua accepted Hermione's offered hug and leant against her for a moment before pulling away. Under normal circumstances she would have stepped out of reach and pretended that she didn't see Hermione's open arms, but these weren't normal circumstances, or at least the normal circumstances she was trying desperately to get back to.

'Look at - oh!' Hermione leapt to her feet. 'They've crashed!'

Angua got up and saw Fred Weasley sprawled in the snow, Harry swooping down to land beside him, and Cheri, who had let go of her broom entirely, covering her face with both hands. Hermione clattered down the wooden steps and Angua followed her.

'I think he's broken his leg,' Harry said as they approached. Fred's freckles stood out on his white cheeks, but he managed a grin when Hermione knelt beside him and took his hand.

'Hurts,' he said.

'I'm sure it does. What happened?'

'I hit him with a Bludger,' Cheri said, getting off her broom, her face distraught. 'Oh, Fred, I'm so _sorry_-'

''f you Ravenclaws got your noses out of a book once in a while you'd learn proper Beating,' Fred said. His eyes fluttered closed. 'Lift to the castle, please?'

Angua took out her wand and levitated him, rather proud that she could perform the spell. Although she was sure that not one of them had so much as a whit of magic in them back home, somehow the transferral between universes had granted them the relevant powers to survive in the universe they'd ended up in. Hermione splinted Fred's leg and they went up to the castle, Fred floating between the two of them.

'Magic would really make moving prisoners a lot easier,' Angua said thoughtfully as they waited for Madam Pomfrey to heal Fred.

'I'm sure it would make a lot of things easier.' Hermione twirled her wand between her fingers. 'I didn't know anything about magic until I was eleven, until I got my letter asking me to come here.'

'But you know so much now - how could you have started with nothing and learned so fast?'

'You learned pretty fast yourself,' Hermione pointed out.

Madam Pomfrey turned away from Fred's bed and smiled at them. 'He's going to heal just fine,' she said. 'It's going to take a while, though, I'm afraid. Normally I could mix up a Bone-Setting Potion in a wink, but the cold snap froze some of Professor Sprout's plants, and they included the comfrey that I need for the potion. I've put it in a cast like Muggles do, but he'll have to be on crutches for about six weeks.'

'Six _weeks_?' Fred yelled indignantly. 'I have Quidditch to play! The first Gryffindor-Slytherin match is just after Christmas!'

Hermione looked at Angua. 'It sounds like Carrot's going to get his chance to play, after all.'


	9. Chapter Eight: Christmas

** __ **

Snow!

Snow that was _white_ instead of a kind of mucky grey! Snow that didn't look suspiciously as though it had passed through someone's digestive system! Snow that _stuck_, and balled up properly when you threw it, and was unlikely to give you any kind of illness in the process!

Vimes ducked as yet another Ravenclaw-constructed snowball went hurtling by his head. He suspected that Cheri was doing something interesting to them, because every time they hit something they exploded in a shower of snow that was at least four times as much snow as could possibly be in the ball in the first place. Despite the fact that he was missing Sybil -- Hogswatchnight was the one night that he'd absolutely put his foot down about this year, intending to spend it with her and Sam -- he was rather enjoying himself.

Over to his left, the Slytherins were huddled together in their snow fort, evidently making some kind of plan. He could see Angua's blonde hair amongst them. Beside him, Carrot was staring at the Slytherins worriedly.

'Sam, I think they're plotting something.'

'I know,' Vimes said. He took a few steps backwards and ran into a pine tree. 'Try not to be under this tree when they charge in, will you?'

'What are you--'

'Just move.' Vimes went up the tree and inched cautiously out along one branch, already bowed by the weight of the snow.

As he'd suspected, the Slytherins were planning an attack on the Gryffindor snow fort, as Lavender's high-pitched squeal shortly indicated. Vimes waited until the blur of colours underneath him was predominantly green, and then bounced on the branch, sending a heavy cascade of snow directly downwards.

It worked about the way he'd thought it would, and he made a mental note to show the trick to Sam sometime, although perhaps with slightly fewer Slytherins yelling for his blood as they dug themselves out of the snowdrift that hadn't been there a minute ago. Angua was there, her face turned upwards, and as he watched she crouched down, about to leap up and catch hold of one of the other branches to swing herself up into the tree --

\-- and then Carrot came cannoning out of nowhere, hitting Angua solidly and tumbling her sideways into the snow. Her shriek could doubtless be heard a mile away, and Vimes grinned, swinging down from the tree and running to help rebuild the wall where the Slytherins had broken through.

He was having _fun_.

* * *

They had what was possibly the best Hogswatcheve -- _no_, he reminded himself, _Christmas, here they call it Christmas_ \-- dinner ever, all worn out and laughing and wet, dripping puddles of water and clumps of snow as they trailed into the Great Hall to eat. Dumbledore's eyes twinkled as he lifted his cup to toast them, and Vimes was not surprised to find that most of the drinks on offer were warm, and tasted faintly of the sort of herbs that Madam Pomfrey frequently utilised for Pepper-Up Potions.

'I trust that you will all sleep well tonight and not spend hours waiting up to see what presents you will undoubtedly all receive in the morning,' Dumbledore said, and Vimes felt a funny sort of internal thud as his stomach reminded him that he wasn't going to be spending Hogswatch with Sam. Sam's _first_ Hogswatch.

Carrot found him in the corner of their dormitory, alone, while everyone else was downstairs and partaking of the Butterbeer that a certain pair of red-haired mischief-makers had brought into the common room. Alone, staring into the white night.

'I wonder if they're still looking for us?' Vimes's voice was hollow.

Carrot squeezed onto the window-seat beside him, and put an arm around his shoulders. 'You know Sybil, Sam -- she'll never stop looking for you. She'll never give up hope. And neither should you.'

They were both quite surprised when Vimes leant his head against Carrot's shoulder and burst into tears.

* * *

Downstairs, down beyond the Gryffindor common room, deep down in the darkness of the dungeons, Angua lay flat on her back on her bed and stared at the ceiling, wondering if Carrot knew she was thinking of him.

* * *

Cheri and Kyla didn't _intend_ to set the Potions dungeon on fire, and even Snape eventually conceded that it was an accident. Eventually.

'We were only trying to help Madam Pomfrey,' Kyla explained, nursing her eyebrows.

'After the big snow fight we were sure she'd need more Pepper-Up Potion,' Cheri put in, hoping that there was some sort of spell to restore one's hair once it had been burned off. If there wasn't, she was sure Sybil would have something for it when they all got home. A wig, if nothing else.

'This dungeon has been the heart of Potions work at this school since before either of you were so much as a fleeting thought in your parents' minds,' Snape said. 'It has -- or, I should say, _had_ \-- the perfect temperature to keep ingredients fresh.' He regarded the smouldering mess they had made of the benches. 'One hundred points from Ravenclaw. Each. And be grateful for the fact that this means I can get the new Potions lab I've been asking for for years, or it would be a _thousand_ points each.'

Cheri and Kyla fled the scene as quickly as they could.

All in all, it was a rather eventful Christmas Eve.

* * *

Vimes managed to make it through Christmas Day by telling himself repeatedly, and firmly, that it wasn't _really_ Hogswatch, similarities or no damned similarities, and when he got back to Ankh-Morpork he could damned well celebrate Hogswatch with Sybil and Sam whenever he damned well liked, damn it.

The support of Carrot, Angua and Cheri helped, admittedly, although it was still strange to hear them calling him 'Sam' instead of 'sir' -- even Carrot had finally got the hang of it.

'This is the way things should be,' said Kyla through a mouthful of mashed potato as they sat and worked their way through the mountain of food on the table. 'Gryffindors and Slytherins and Ravenclaws -- and Hufflepuffs, too, of course -- all together, not divided. It's a shame none of you ended up in Hufflepuff. The four of you have really shown everyone else that it's possible to have inter-House friendships.' She said this as sagely as someone with no eyebrows could.

'Sybil would be in Hufflepuff,' Vimes said.

'She would. And Detritus would be in Gryffindor,' said Angua. 'Brave, but not what you'd call bright.' She ducked a lazy swat from Vimes, laughing.

'And Nobby would make an interesting specimen for Care of Magical Creatures,' Cheri said, provoking giggles from everyone.

'What about Lord Vetinari?' Kyla asked.

'Slytherin,' the other four said in unison, without even needing to think about it.

'Gods, can you imagine the havoc he'd wreak here?' Carrot asked. 'He'd be like that dark wizard, He Who Must Not Be Named, only worse.'

Kyla shuddered with distaste and hastily changed the subject.

* * *

At last it was time for the Quidditch match against Slytherin, and though Vimes, Angua and Cheri sat together in the stands, all three of them could sense that this was one of the ultimate divisions of the Houses, even more so than classes or the dinner tables.

Carrot came out onto the field with the others, and Angua admired again the cut of his Quidditch robes. The brilliant red suited him in a way the dingy red of his Watch shirt didn't quite manage to achieve. She'd been there when he'd first tried the robes on, and only the intervention of Madam Hooch had stopped her from fully showing the extent of her appreciation for the way they made him look.

The game began, and it was immediately apparent that Carrot was still less than perfect regarding his broom-handling skills. He lurched around a lot, and Angua flinched as a Bludger narrowly missed knocking him off the broom altogether.

'I hope he doesn't fall,' Vimes said.

'Don't say that! You'll jinx him!' Cheri was bouncing on her seat, partly out of anxiety, partly because Hagrid was sitting in front of them and she couldn't see past him.

Fred Weasley manoeuvred himself along the row to sit beside them, almost KOing several people with his crutches on the way. 'Blimey, he looks uncomfortable out there,' he commented. Kyla followed him, looking strangely guilty and clutching something under her robes.

Angua shot him a filthy look. 'Well, if you hadn't broken your leg, he wouldn't _be_ out there,' she said. 'He looks like he's going to break his neck!'

Kyla looked even guiltier. 'Um,' she said. 'I hope he doesn't.'

'We _all_ hope he doesn't,' Vimes said, flinching as a Bludger whirred about an inch past Carrot's head and Carrot took a blind swing at it.

'Because,' Kyla continued, 'I think I've found the book.'

'You've _found_ it?' 'Where was it?' 'How do you know?' Cheri, Fred and Vimes questioned her.

'_Carrot_!' Angua shrieked, leaping to her feet and vaulting over Hagrid towards the playing field.

The others turned and saw what she'd seen: Carrot had fallen from his broom and was lying on the grass, the red of his robes like blood against the green, lying too still to be all right.


	10. Chapter Nine: Night Watch

Madam Pomfrey had specified no visitors. Not just one at a time. _No_ visitors.

Angua sat in a soft armchair just outside Carrot's room, her head in her hands. Cheri perched on the arm of the chair, awkwardly trying to comfort her. Kyla sat across from them, turning the missing book over and over in her hands. Vimes paced up and down the rug between them.

They had been sitting (or pacing) their silent vigil for an hour before Angua looked at Kyla and spoke. 'Where was it?' Her voice came out croakily -- she'd screamed very loudly when she'd seen Carrot fall. She swallowed and tried again. 'Where was the book?'

'It was just on my shelf with the other fiction books. I borrowed it last term and forgot that it was a library book, not one of my own. I've got a lot of books that used to belong to libraries -- Muggle libraries -- and they all have similar stickers on them.' Kyla looked up, but was unable to directly meet Angua's eyes. 'I'm sorry. For what it's worth, I wish I'd realised sooner.'

'It'll be all right,' Cheri said. 'Madam Pomfrey will fix whatever's wrong with him, and he'll be fine.'

'He landed on his _head_, Cheri,' Angua said, not quite in a growl. 'People don't just get up and walk away from things like that.'

'You'd be surprised,' Kyla said. 'Madam Pomfrey's used to treating outrageous injuries.'

Vimes said nothing. He was thinking of how this would've played out had they been at home. True, had they been at home Carrot wouldn't have been gadding about on a broomstick, but he could easily have fallen off a roof, and people did not fall off Ankh-Morpork's roofs without substantial injury. The magical healing that Kyla was waving off as commonplace was unfamiliar to Vimes, and he wondered whether the wizards back at home would have anything quite like it. Somehow, he doubted it. They seemed to be more into things that looked impressive -- they were almost as bad as the Alchemists' Guild for explosions -- than things that were ever actually _helpful_.

If this had happened at home, Carrot wouldn't be on the other side of the white door, lying in a soft bed with a competent healer watching over him and making him better with magic. Carrot would be inside a pine box, and there wouldn't be a healer, but a priest. Probably a dwarf priest of some sort. There'd be a funeral, and everyone -- _everyone_ \-- in Ankh-Morpork would be there.

Vimes shook his head. Angua noticed, and smiled wanly.

'Thinking morbid thoughts, sir?'

'Might be, sergeant.'

'Stop it, sir.'

'Yes, sergeant.'

Kyla laughed quietly. 'That just sounds wrong, you two.'

'Only because we're younger than usual,' Vimes said. 'It sounds ridiculous coming from a couple of teenagers.'

The white door opened and all talking ceased as they turned to look at Madam Pomfrey.

'Concussion, broken collarbone, broken left arm, bruised ribs, sprained right ankle,' she listed. 'He's going to need a lot of rest and sleep over the next few days to recover. I've done what I can, but the rest is down to natural healing.'

'You mean he's not dead?' Angua asked.

Madam Pomfrey looked at her quizzically. 'Of course not. But he needs to remain undisturbed and--' Whatever she had been about to say was cut off as Angua barged past her.

'I'd let her stay for a little while,' Vimes suggested. 'Things can get pretty hairy when she's upset.'

* * *

It took a week before Carrot was allowed to leave the hospital wing. The others carried on with their classes in that time, especially Cheri, who was frantically noting down as much as she could learn in Potions in the hope that it would somehow be useful back home if she could replicate the ingredients. Angua, of course, spent every spare moment in the hospital wing.

Vimes, on the other hand, was counting the hours until they could go home. He paid little attention in class, but most of the professors overlooked it, except Snape, who never let _anyone_ get away with slacking off.

Finally, though, Carrot was freed from the hospital wing, and the four of them made their way down to the library, saying their goodbyes on the way. Carrot's ankle had healed enough to walk on, which was fortunate, because his left arm was still in a cast and crutches were difficult enough to use with two working arms. Kyla had burst into tears and apologised at least twenty times when she'd seen the state he was in, as if her forgetting she had the precious book was the sole thing that had caused his crash landing.

Dumbledore and Madam Pince were the only two in the library, though a lot of people were waiting in the corridors to find out what would happen, whether replacing the book on the shelf would send the four back to their own world.

'If it transpires that there is a way for you to return here at some future time, do you think you will?' Dumbledore asked.

Vimes shook his head. 'Not me. I might send some of the wizards, though. They could do with meeting Professor Snape.'

'I'd like to learn more about your Potions,' Cheri volunteered.

Angua just looked at Carrot's bandaged body and rolled her eyes.

Madam Pince handed the book to Vimes, who held it in one hand and took Cheri's hand in his free hand. 'Don't let go,' he said. 'We don't want to end up in another world, or worse, trapped between worlds.'

'Take care,' Madam Pince said, although whether she was referring to them or to the book, Vimes wasn't sure.

Taking a deep breath, Vimes slid the book back into the proper spot on its shelf.

* * *

'Oook? Oook oook _oook_!'

'Sounds like home,' Angua commented dryly.

Carrot doubled over, wincing; apparently, the return to his usual age and body size hadn't worked wonders for his broken arm. The cast split and fell off, and he clawed at the bandages around his ribs that were suddenly a tad too tight. 'Has anyone got a pair of scissors?' he wheezed. Cheri set to trying to unwind the bandages.

Vimes looked at the bookshelf. The gap in the books was gone, replaced by a fat volume titled _Harry Potter and the Order of the Phoenix_. Its garishly coloured cover seemed out of place amongst the brown tomes surrounding it. _Well_, he thought, _at least we'll know where to go if we want to reopen the portal_.

Colon and Nobby appeared, dashing around the corner of the nearest set of shelves and skidding to a halt. 'You're back! Where have you _been_?'

'Gods, you look terrible,' Nobby added, looking at Carrot.

Cheri ignored them both and scurried past them, riffling through the sheaf of parchment that she carried as she went, already muttering something about Pepper-Up Potion.

'Fred, help Angua get Carrot somewhere he can lie down. Nobby... try not to infect him with anything, he's already sick enough as it is. Where's Lady Sybil?' Vimes asked.

'She's up at your house,' Nobby said. 'She said she knew you was comin' back eventually, and she said she'd wait there.'

'Right,' Vimes said. He tried not to shove Carrot too hard on his way past, but the library aisles weren't very wide. 'Sorry. I'll see you all back at the Watch House in... oh, call it a week.'

'Sir?'

'I'm taking a holiday, Angua. Schoolkids need one, once in a while.' And with that he broke into a run, out of the Library, out of the University, and all the way home without stopping once.

* * *

Sybil was upstairs in the nursery, reading to Young Sam, who looked up as Vimes's boot made the merest creak on the squeaky floorboard. 'Dada!' he cried gleefully. 'Dada home!'

Sybil looked up at her son's words and almost dropped him as she leapt to her feet. 'Sam!'

Vimes crossed the room and threw his arms around both of them, squeezing Young Sam between himself and Sybil (Young Sam squealed again and shouted, 'Squish!'). 'I'm home,' he said, feeling a lump rise in his throat. 'It's good to be home. It's good to be older than fifteen.'

'Sam, what _are_ you talking about?'

Vimes drew back a little, settling Young Sam on his hip, and smiled. 'It's a long story.' He leaned closer and kissed her, and she kissed him back, clinging to him. 'Why don't we go downstairs and talk about it over dinner? I've missed your cooking.'

Sybil laughed. 'Wherever you've been must have been pretty bad if you missed _my_ cooking.'

Vimes put his free arm around her waist. 'It was bad because it wasn't _yours_.'

They went downstairs together; before long, the smell of burning bacon drifted through the house, along with the sound of a series of animal noises from Vimes and the accompanying shrieks of delight from Young Sam, who was already learning that books could be very wonderful things... provided that one didn't get _too_ far into them, of course.

**The End**


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